Heavier hydrocarbon materials include FCC/RCC slurry oil, asphalt, petroleum pitch and the like.
Heavier hydrocarbon materials also include automotive lubricating oils which are usually formulated from paraffin based petroleum distillate oils or from synthetic base lubricating oils. Lubricating oils are combined with additives such as soaps, extreme pressure (E.P.) agents, viscosity index (V.I.) improvers, antifoamants, rust inhibitors, antiwear agents, antioxidants, and polymeric dispersants to produce an engine lubricating oil of SAE 5 to SAE 60 viscosity.
After use, this oil is collected from truck and bus fleets, automobile service stations, and municipal recycling centers for reclaiming. This collected oil contains organo-metallic additives such as zinc dialkylthiophosphate from the original lubricating oil formulation, sludge formed in the engine, and water. The used oil may also contain contaminants such as waste grease, brake fluid, transmission oil, transformer oil, railroad lubricant, crude oil, antifreeze, dry cleaning fluid, degreasing solvents such as trichloroethylene, edible fats and oils, mineral acids, soot, earth and waste of unknown origin.
Reclaiming of waste oil is largely carried out by small processors using various processes tailored to the available waste oil, product demands, and local environmental considerations. Such processes at a minimum include chemical demetallizing or distillation. The presence of organo-metallics in waste oils such as zinc dialkylthiophosphate results in waste oils becoming sticky, overly viscous and thus difficult, if not impossible, to process. Moreover, the resulting sludge created reduces the amount of salable product, as well as creating additional disposal problems.
Successful reclaiming processes require the reduction of the organo-metallics (or ash) content to a level at which the hot oil does not become sticky. Such reduction can be carried out by chemical processes which include reacting cation phosphate or cation sulfate with the chemically bonded metal to form metallic phosphate or metallic sulfate. U.S. Pat. No. 4,432,865 to Norman, the contents of which are incorporated herein by reference, discloses contacting used motor oil with polyfunctional mineral acid and polyhydroxy compound to react with undesired contaminants to form easily removable reaction products. These chemical processes suffer from attendant disposal problems depending on the metal by-products formed.
Ash content can also be reduced by heating the used lubricating oil to decompose the organo-metallic additives. However, indirect heat exchange surfaces cannot be maintained above 400° F. (204° C.) for extended periods without extensive fouling and deposition of metals from the additives. Used lubricating oils can be heated to an additive decomposition temperature of 400° F. (204° C.) to 1000° F. (538° C.) by direct heat exchange by mixing with a heated product oil as disclosed in U.S. Pat. No. 5,447,628 to Harrison, et al., the contents of which are incorporated herein by reference. However, dilution of the product oil with used oil obviously suffers from the inefficiency of reprocessing already processed product oil, as well as rapid fouling of reactor surfaces. U.S. Pat. No. 4,101,414 to Kim, et al., incorporated herein by reference, discloses predistillation by steam stripping for several hours of a used lubricating oil stock in order to remove light oil, residual water, sulfur, and NOx. The temperature is kept at temperatures which avoid additive breakdown, and the process provides a concentrate product upon vacuum distillation. Flow processes using heat exchange by direct contact with hot hydrogen have been proposed but are expensive in view of the costs associated with hydrogen compression and hydrogen's low heat capacity. Such processes include UOP's Hy-Lube described in U.S. Pat. Nos. 5,244,565 and 5,302,282 which feature an initial used oil feed fractionation step to remove sludge and a majority of metals utilizing a hot circulating hydrogen stream as a heating medium to avoid deposition of decomposed organo-metallic compounds on heating surfaces, followed by a hydrotreating circuit with caustic neutralization to eliminate chlorides, with a final product fractionation step. Flow processes utilizing steam have also been proposed. However, even when used motor oil is directly heated, i.e., in the absence of heat transfer surfaces, the nozzles and downstream piping can plug in 24 to 72 hours due to the presence of organo-metallic compounds.
In particular, extensive work has been reported in the patent literature on use of large amounts of hot, high pressure hydrogen for vaporization of used motor oil (UMO). While such processes are certainly technically feasible, there are significant capital costs associated with the relatively high pressure operation reported (typically 500 psig). Operation at high pressure makes it difficult to vaporize the used lube oil components, so higher hydrogen addition/circulation rates are used to facilitate vaporization, with hydrogen circulation rates of 10,000-18,000 SCFB being reported. Hydrogen helps suppress some condensation coking reactions that otherwise could occur in the heating and vaporization step. The hydrogen is also present in an amount sufficient to supply the hydrogen demand of a downstream hydrotreating reactor. This combination, high-pressure hydrogen coupled with downstream hydrotreating, can produce a liquid product from a UMO fraction which is excellent for use as either a lube stock or as cracker charge.
Representative hot hydrogen UMO processes include:
U.S. Pat. No. 4,806,233, James, Jr., et al., Method Of Separating a Hot Hydrocarbonaceous Stream
U.S. Pat. No. 4,818,368, Kalnes, et al., Process for Treating a Temperature-Sensitive Hydrocarbonaceous Stream Containing a Non-Component to Produce a Hydrogenated Distillable Hydrocarbonaceous Product
U.S. Pat. No. 4,840,721, Kalnes, et al., Process for Treating a Temperature-Sensitive Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Hydrogenated Distillable Hydrocarbonaceous Product
U.S. Pat. No. 4,882,037, Kalnes, et al., Process for Treating a Temperature-Sensitive Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Selected Hydrogenated Distillable Light Hydrocarbonaceous Product
U.S. Pat. No. 4,923,590, Kalnes, et al., Process for Treating a Temperature-Sensitive Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Hydrogenated Distillable Hydrocarbonaceous Product
U.S. Pat. No. 4,927,520, Kalnes, et al., Process for Treating a Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Hydrogenated Distillable Hydrocarbonaceous Product
U.S. Pat. No. 5,004,533, Kalnes, et al., Process for Treating an Organic Stream Containing a Non-Distillable Component to Produce an Organic Vapor and a Solid
U.S. Pat. No. 5,013,424, James, Jr., et al., Process for the Simultaneous Hydrogenation of a First Feedstock Comprising Hydrocarbonaceous Compounds and Having a Non-Distillable Component and a Second Feedstock Comprising Halogenated Organic Compounds
U.S. Pat. No. 5,028,313, Kalnes, et al., Process for Treating a Temperature-Sensitive Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Distillable Hydrocarbonaceous Product
U.S. Pat. No. 5,068,484, James, Jr., et al., Process for the Hydroconversion of a Feedstock Comprising Organic Compounds Having a Tendency to Readily Form Polymer Compounds
U.S. Pat. No. 5,102,531, Kalnes, et al., Process for Treating a Temperature Sensitive Hydrocarbonaceous Stream Containing a Non-Distillable Component to Produce a Distillable Hydrocarbonaceous Product
U.S. Pat. No. 5,176,816, Lankton, et al., Process to Produce a Hydrogenated Distillable Hydrocarbonaceous Product
U.S. Pat. No. 5,244,565, Lankton, et al., Integrated Process for the Production of Distillate Hydrocarbon
U.S. Pat. No. 5,302,282, Kalnes, et al., Integrated Process for the Production of High Quality Lube Oil Blending Stock
U.S. Pat. No. 5,316,663, James, Jr., Process for the Treatment of Halogenated Hydrocarbons
U.S. Pat. No. 5,354,931, Jan, et al., Process for Hydro-treating an Organic Feedstock Containing Oxygen Compounds and a Halogen Component
U.S. Pat. No. 5,384,037, Kalnes, Integrated Process for the Production of Distillate Hydrocarbon
U.S. Pat. No. 5,401,894, Brasier, et al., Process for the Treatment of Halogenated Organic Feedstocks
U.S. Pat. No. 5,552,037, Kalnes, et al., Process for the Treatment of Two. Halogenated Hydrocarbon Streams
U.S. Pat. No. 5,723,706, Brasier, et al., Process for the Treatment of Halogenated Organic Feedstocks
U.S. Pat. No. 5,817,288, Bauer, et al., Process for Treating a Non-Distillable Halogenated Organic Feed Stream
U.S. Pat. No. 5,904,838, Kalnes, et al., Process for the Simultaneous Conversion of Waste Lubricating Oil and Pyrolysis Oil, Derived from Organic Waste to Produce a Synthetic Crude Oil
While this approach is excellent in terms of product quality, the capital and operating expense of such an approach are significant.
The present invention is an improvement over the commonly owned U.S. Pat. Nos. 6,068,759 and 6,270,657 which disclose a process for recovering lube oil base stocks from used lubricating oil formulations containing base oil stock and organo-metallic component by directly contacting used lubricating oil with a heated vapor, e.g., steam, under conditions which at least partially decompose the organo-metallic component and provide a desired volume of pumpable bottoms containing organo-metallic compound decomposition products and an overhead comprising gases and distillable hydrocarbons, with no substantial carryover of metals into the overhead.
The present invention is also an improvement over the commonly owned U.S. Pat. No. 6,402,937 which discloses a process for thermally processing/vaporizing UMO by direct injection of superheated vapor into a UMO vaporization vessel.
Further, while there has been extensive use of high pressure hydrogen for vaporization and subsequent hydrotreating of UMO, such a process has never included the use of a combination of superheated steam and a reaction gas to i) promote oxidation and thermal reaction of heavier hydrocarbons, while simultaneously ii) removing volatile components with a steam stripping process.
The present invention is also an improvement over the commonly owned U.S. Pat. No. 6,402,938 which discloses a process for recovering. UMOs by heating a compressed recycled vapor to produce a superheated vapor; such process requires compression of the vapor without hydrogenation of the UMO.
Until the present invention there has not been a process that could be used to promote oxidation and thermally process/vaporize heavier hydrocarbons by direct injection of a combination of superheated steam and reaction gases.
It would be advantageous to provide an efficient method for oxidizing and thermally reacting heavier hydrocarbons in a process which upgrades and/or recovers large quantities of hydrocarbon materials in a continuous manner.
It would also be advantageous to provide an efficient method for oxidizing and thermally reacting heavier hydrocarbons in a process which does not require apparatus susceptible to clogging or fouling under the conditions encountered during decomposition of metallic additives. It would also be advantageous to provide a process for treating heavier hydrocarbon material which does not require pre-separation of lighter and/or volatile materials or water typically found in the heavier hydrocarbon materials as collected.